MCQ On Nitrogen Cycle

Nitrogen cycle is a biogeochemical process by which atmospheric nitrogen is converted into chemical forms to make it available for living organisms and is returned back into the atmosphere. This process is carried out through several biological and physical process.

To know about Nitrogen Cycle and its processes in complete detail click on the link below.

Link: Nitrogen Cycle

Nitrogen Cycle MCQs

1. Which of the following statements is correct?

  1. Atmosphere is the major reservoir for plants
  2. Nitrogen is the most abundant nutrient for plants
  3. Nitrogen cycle is a sedimentary cycle
  4. All

2. Nitrogen is absorbed by the plants in the form of

  1. Ammonium
  2. Nitrites
  3. Nitrates
  4. All

3. Nitrogen fixation is the conversion of

  1. N2 to N
  2. N2 to NH3
  3. N2 to NO3
  4. N2 to urea

4. Important enzymes involved in nitrogen fixation are

  1. Nitrogenase and hydrogenase
  2. Nitrogenase and hexokinase
  3. Nitrogenase and peptidase
  4. Nitrogenase and hydrolyase

5. Symbiotic nitrogen fixing cyanobacteria are not present in

  1. Azolla
  2. Gnetum
  3. Anthoceros
  4. Cycas

6. How many molecules of ATP are required to fix one molecule of nitrogen?

  1. 12
  2. 20
  3. 6
  4. 16

7. Ammonification is formation of

  1. Ammonia from nitrates by decomposers
  2. Ammonia from nitrogen
  3. Ammonia from amino acids
  4. Ammonia from nitrates by nitrogen fixers

8. Conversion of nitrates to nitrogen is called

  1. Ammonification
  2. Nitrification
  3. Nitrogen fixation
  4. Denitrification

9. Conversion of nitrites to nitrates is called

  1. Nitrosococcus
  2. Clostridium
  3. Nitrobacter
  4. Nitrosomonas

10. Conversion of ammonia to nitrite and then to nitrates is called

  1. Ammonification
  2. Denitrification
  3. Assimilation
  4. Nitrification

Answer Key


2- d

3- b

4- a

5- b

6- d

7- c

8- d


10- d

Other Interesting Topics

Important questions for class 11

Important questions for class 12

Biology MCQs